If it were up to me, I'd have the rules require 7 riffle shuffles as the last thing to happen before presenting, period, at any level of play. I think part of the problem is that the casual "kitchen-table" playerbase, as a whole, doesn't know how to shuffle, or at least doesn't enforce proper shuffling, whether because they feel it takes too long, or damages cards, or whatever the reason. So, when those kitchen-table casual players move on to become FNM players, and eventually even tournament players, they take their bad shuffling habits with them.
The problem is that there are those that are just unable to riffle shuffle a sleeved deck well, even worse with double-sleeved decks. I can sort of do it, but I have large hands and long fingers. My oldest son (19) has his mother's short fingers and has a degree of dyspraxia so he has a harder time with it than I do. Now, if you mean "quality riffle or mash shuffle" then I would agree 100%, but honestly other than hand over hand, which is not really shuffling per-se.
We've all seen people randomizing their decks by dealing them out into stacks and then putting them back together.
Being a math/computer nerd I wondered if there was a pattern to the reconstructed decks.
Well, it turns out that there is. After some computer simulations and a lot of trial and error number juggling, I derived a formula for predicting the order the cards will be in after a stack shuffle.
Take a deck with n cards listed from the top down as card 0, card 1...card n-1.
I'm starting with zero in my lists because of modulo arithmetic and computer arrays.
Deal them out into s stacks starting with stack 0, stack 1... stack s-1.
Then put stack 1 on top of stack 0, stack 2 on top of stack 1 and continue until stack s-1 is on top.
The card in position x will be in position P(x) afterwards. Where
P(x)=(n-1)-( (x%s) * (n/s) * (x/s) + b )
b= x%s if x%s < n%s
b= n%s if x%s >= n%s
All divisions are integer divisions (truncate the fractional part) and % is modulo division.
I'll explain the terms in the formula.
Since stack shuffling reverses the order of the cards we subtract from (n-1).
If you had only one stack you would simply be reversing the order of the whole deck and the formula would reduce to P(x)=(n-1)-x.
Stack number * Stack size * Position in stack + Shift
(x%s) * (n/s) * (x/s) + b
Shift accounts for using a number of stacks that doesn't divide evenly into the deck size.
That means that the stacks wouldn't all be the same size and the new positions above the larger stacks get shifted up by the difference in size.
Incidentally if you put the stacks back together in reverse order (stack s-1 on the bottom, stack 0 on top)
P(x) = (n-1)- ( (s-1-x%s) * (n/s)*(x/s) +b
b=n%s-x%s-1
if b<0 then b=0
I'm not a competitive Magic player and I don't want this used for cheating.
Quite the opposite, I want this out there so people are aware of it. I'm sure I'm not the only person who thought of it.
It's easily defeated by insisting that the stacks are not put back together in order or doing a riffle shuffle beforehand.
This was just a fun mathematical exercise and I thought some of you other math Magic nerds out there might appreciate it.
The best thing to do is riffle their decks as much as you can in 30 seconds.
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Card advantage is not the same thing as card draw. Something for 2B cannot be strictly worse than something for BBB or 3BB. If you're taking out Swords to Plowshares for Plummet, you're a fool. Stop doing these things!
If someone just stack shuffles their deck and maybe overhand shuffles it, then presents, you get a couple options. You can call a judge so they are aware that their deck is not random and not shuffled and that they just wasted a bunch of time (personally my favorite) or you can shuffle the crap out of their deck(what I do at FNMs). Anything higher then FNM call a judge. They can get assessed warnings and penalties for this. It also helps curb cheating at events from people stacking their deck.
I'm pretty sure it is now common place that you can stack shuffle in order to 'disperse' the cards, but as many have said, the riffle shuffle or other equally random shuffling technique should be used to randomise the deck properly. I remember at a GP some guy was 'shuffling' by separating lands and spells, then just placing them in a stack with 1 land to every 2 spells... called a judge for that.
I'm pretty sure it is now common place that you can stack shuffle in order to 'disperse' the cards, but as many have said, the riffle shuffle or other equally random shuffling technique should be used to randomise the deck properly. I remember at a GP some guy was 'shuffling' by separating lands and spells, then just placing them in a stack with 1 land to every 2 spells... called a judge for that.
Anyway, nice work on the formula!
You may pile "shuffle" or stack "shuffle" your deck all you want, but it is not random and it is not considered shuffling hence the "". You must mash or riffle shuffle your deck multiple times after each time you pile/stack your deck. About the only good thing pile/stacking your deck does is allows you to count your cards easily because a random deck is absolutely random. People pile then overhand their deck then hand it to me all the time in Japan and then get a judge warning at least 3-4 times a month when I am playing in tournaments because they don't know how to properly shuffle a deck. It's gotten to the point where at the beginning of a round and they hear a judge call they already know what the problem is and start the explanation about why that person is getting a warning and what they should be doing with their deck.
I would absolutely love to break people of the habit of piling their deck because it is a huge waste of time. Pick up your cards after a game and start mashing or riffling what you used in that game to randomize that pile and then mash/riffle the deck and the played cards after that. It will better accomplish what you are trying to do in about half the time. Especially useful if you are a slow player to begin with and go to time often.
I like to pile shuffle my deck once after every match just to count it and make sure no cards were lost (surprisingly common with all the Banishing Lights and Detention Spheres floating around). Then I will mash a couple of times and maybe do some overhands before presenting. I don't try to do it particularly quickly. I just do it at a reasonable pace.
Personally I care more about keeping my cards in pristine condition than having them be 100% randomized. I've got a set of Masques Brainstorms I've been playing for more than ten years and they still look like they just came out of a pack. You can hold them up to a light source in an angle and not see any scratches at all. My focus when shuffling is to avoid damaging the cards. Luckily I play in Japan and people here tend to be careful with another dude's cards, but I watch them like a hawk as they start shuffling and if they look like they'll crease the cards I get a judge to shuffle my deck instead. It hasn't come to this yet, but I actually have no problem conceding a match or dropping out of an event to keep my cards mint. Hopefully nobody ever finds out that they can insta-win against me by threatening to bend my cards.
I like to pile shuffle my deck once after every match just to count it and make sure no cards were lost (surprisingly common with all the Banishing Lights and Detention Spheres floating around). Then I will mash a couple of times and maybe do some overhands before presenting. I don't try to do it particularly quickly. I just do it at a reasonable pace.
Personally I care more about keeping my cards in pristine condition than having them be 100% randomized. I've got a set of Masques Brainstorms I've been playing for more than ten years and they still look like they just came out of a pack. You can hold them up to a light source in an angle and not see any scratches at all. My focus when shuffling is to avoid damaging the cards. Luckily I play in Japan and people here tend to be careful with another dude's cards, but I watch them like a hawk as they start shuffling and if they look like they'll crease the cards I get a judge to shuffle my deck instead. It hasn't come to this yet, but I actually have no problem conceding a match or dropping out of an event to keep my cards mint. Hopefully nobody ever finds out that they can insta-win against me by threatening to bend my cards.
Double sleeve your deck. KMC perfect fits are 200yen in Japan. It's worth it and helps with any bending issues from shuffling. Also helps prevent against moisture getting to the cards. Even a fairly strong mash shuffle shouldn't hurt double sleeved cards.
I totally agree and in fact I already double-sleeve all my decks. I used to have them all in KMC perfect-fits in KMC sleeves, but recently I have been trying out these sturdy-feeling sleeve guards I found at Amenity Dream. They are almost exactly like the ones made by KMC (http://www.hareruyamtg.com/product/80524) except they don't have the silver patterns in the corners and they only cost around Y190. I still use perfect-fits for the cards in my binder.
Note: If you're like me at all, you're thinking right now that the best way to do things is to triple-sleeve the deck in perfect-fits, then a regular sleeve, then a sleeve guard. I've tried this and unfortunately the deck becomes way too thick when you do it that way.
We've all seen people randomizing their decks by dealing them out into stacks and then putting them back together.
Being a math/computer nerd I wondered if there was a pattern to the reconstructed decks.
Well, it turns out that there is. After some computer simulations and a lot of trial and error number juggling, I derived a formula for predicting the order the cards will be in after a stack shuffle.
Take a deck with n cards listed from the top down as card 0, card 1...card n-1.
I'm starting with zero in my lists because of modulo arithmetic and computer arrays.
Deal them out into s stacks starting with stack 0, stack 1... stack s-1.
Then put stack 1 on top of stack 0, stack 2 on top of stack 1 and continue until stack s-1 is on top.
The card in position x will be in position P(x) afterwards. Where
P(x)=(n-1)-( (x%s) * (n/s) * (x/s) + b )
b= x%s if x%s < n%s
b= n%s if x%s >= n%s
All divisions are integer divisions (truncate the fractional part) and % is modulo division.
Question: if the person doing the piling did not go sequentially, stack 0, stack 1, ... stack N, though, and kinda haphazardly went from stack 0 to stack N to stack 4, and kept changing it up with each pass, and mashed the piles together, would that impact the ability to accurately predict it at all?
I ask because at least where I am, nobody does their piling sequentially, whereas I have grown fond of piling first, then doing mashes and riffles, and I was curious if sequences, the number of patterns, etc would make it a bit harder to predict mainly because I love to ponder those sorts of things.
I prefer the legal method of shuffling: Any method that sufficiently randomizes your deck. In one legacy matchup, going into game three in a belcher vs belcher mirror, I took the time to take my deck, and flip a coin to determine whether each card went on the top or the bottom of the new pile. I repeated this process enough to shuffle the deck three times, since my opponent graciously allowed me to take however long it took him to go across the street to pizza hut to shuffle, provided our judge watched to make sure I didn't stack my deck. Needless to say, we still finished before the loam pox v miracles match finished. He made 16 goblins and passed, then I cast and activated a belcher for 19 (hit that one land, damn it), and topdecked the LED to actually win the belcher mirror on the draw!
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Yes, I am a local area mod. WELP. GOOD LIFE CHANGES ALL HAPPEN AT ONCE AND SOME ARE MUTUALLY EXCLUSIVE
Primary Decks:
Modern: Esper Draw-Go
Legacy: RUG Lands
EDH: Sidisi turn-3 storm
The biggest issue is that the population at large doesn't actually understand what randomness is. And the problem with that is that it's an issue you can't explain to anyone before heads end up buried in the sand because "That doesn't sound random" to them. With actual randomness you'll flood sometimes; with what MTG players think is random, you'll hardly ever flood.
I absolutely detest whenever anyone tells me that pile shuffling by a number the deck is divisible by isn't as random as shuffling by some arbitrary prime. You do not know what random is! No matter what number you use the deck will not be sufficiently random. No matter what you do your making a neat and ordered deck with minimal clumps! I pile shuffle for three reasons:
1) I'm lazy.
2) No one here is using a sufficiently randomized deck, so why should I put myself at a disadvantage. The alternative is to explain to everyone why they shouldn't shuffle like they are, and once again, I'm lazy.
3) At this REL (And by "this REL" I mean the nonexistant one for casual play) it just doesn't matter and minimizing manascrew is probably just for the best anyway.
The biggest issue is that the population at large doesn't actually understand what randomness is.
Its certainly not a good point to "cheat" , and yea, i would count knowingly not shuffling a deck cheating, you are trying to get an advantage.
Its quite easy to combat this, explain it in an open round, not 1 for 1.
That will make up for quite a lot, if they have questions, they can go ahead and any sain person will respect that, especially if its explained by a judge or any half decent person.
If you established this, people should spread the word and if they see someone doesnt shuffle properly, tell them to riffle shuffle, show them how to, its good for everyone.
By that, its totally fine to pile shuffle, count the cards, then riffle quickly and your done. If that becomes routine, its fine, doesnt take even a minute.
Just dont make up the lie that everyone is cheating, so cheating is ok. Thats just the source of all evil, someone has to start and make things go right, its just about anything in life, someone has to make the start and get a respectable front runner to kickstart the process.
If people want to get better, they have to play better, not cheat, its as easy as that.
It is commonly believed that 7 riffle shuffles are sufficient to randomize a deck based on a journal article published in 1992. However a more recent journal article explores the issue in more depth. Two quotes from the article are "The following two games use rising sequences to take advantage of how the GSR- shuffle is defined. They expose a lack of true randomness created by seven riffle shuffles." and "A computer program was written, which selected the most likely card to be at the top after a number of riffle shuffles. The results for the probability of success are displayed in the following table, where k is the number of riffle shuffles and m the number of guesses allowed to the computer. Given 26 guesses for a deck shuffled 8 times, the program succeeded 54.8% of the time. If the deck were truly random, then the success rate should be 50%." The program guessed correctly 59.6% of the time after 7 shuffles and 51.3% after 10 riffle shuffles. I don't know how to paste the table here so the full article is http://math.uchicago.edu/~may/REU2013/REUPapers/Guo.pdf
Keep in mind that this research was for a 52 card deck so a 60 card deck would be less randomized by 7 riffle shuffles than this research indicates.
I agree that this is the best method we have for mixing our decks. My point is that it is not randomized after 7 really good riffle shuffles. 10+ has a better chance of doing a good job so if your opponent shuffles 7 times it is a good idea to shuffle his deck another 7 times to approach a randomized deck. Most people, myself included, are probably not good enough at shuffling to mix a deck enough to randomize it with the minimum number of shuffles. I don't think that people are trying to cheat but playing with physical cards is different than playing MTGO because MTGO is truely randomized and most games of physical magic are not. To improve my mtg skill I want to play games with randomized decks so that my choices in deck building (numbers of lands, balance of spells to creatures) can be made with better information. If other people want to achieve more randomness in their decks I think they should know that they should be shuffling more than 7 times.
I agree that this is the best method we have for mixing our decks. My point is that it is not randomized after 7 really good riffle shuffles. 10+ has a better chance of doing a good job so if your opponent shuffles 7 times it is a good idea to shuffle his deck another 7 times to approach a randomized deck. Most people, myself included, are probably not good enough at shuffling to mix a deck enough to randomize it with the minimum number of shuffles. I don't think that people are trying to cheat but playing with physical cards is different than playing MTGO because MTGO is truely randomized and most games of physical magic are not. To improve my mtg skill I want to play games with randomized decks so that my choices in deck building (numbers of lands, balance of spells to creatures) can be made with better information. If other people want to achieve more randomness in their decks I think they should know that they should be shuffling more than 7 times.
Well, the math behind the number is that that would be the case to archive a random deck in a scenario that isnt really about handling "real" cards.
If you riffle you will archive more and less randomization than the math example would imply, as you might move cards more and in bigger blocks.
What makes riffle shuffles really good randomization is doing them "not" perfect (as putting each 1on1 in exactly half the deck doesnt really do anything).
----
After 7 riffles a deck should be sufficiently random, for any intens and purposes that a game would want to have (especially if the other player performs just like ~2 extra riffles on his own, its as random as it will be and doesnt use too excessive amounts of time).
Doing more and much more shuffling gets to a point in which it simply eats up time and doesnt really archive anything meaningful.
Most will not even do 7 riffles, and just cut and mash like ~3 times.
Usually still enough, especially in Limited, when the opponent then mashes the deck ~2+ times its pretty much sufficient.
----
The most iconic problem with not enough shuffling is when someone can actually predict where a card will end up, which you can easily do, if theres not enough shuffling involved (like the card on the very bottom will be at the bottom after just 3 mash/riffle shuffles, you really need a bunch to fully move cards around).
The classic is when people put like a pile of 10+ lands after a game in there deck, and riffle/mash that just like 3 times. Ofcourse that stack of lands wont really disappear from that, and so they end up hurting themselves (and dont know they did it on their own).
Commonly people will "learn" to mana-weave their deck, which will avoid that problem, but only really means they shuffle even less, and "think" they do the right thing, as it clearly doesnt hurt them anymore.
At some point if people understand what they are doing, they will shuffle more, but here again comes a point where people shuffle so much that it doesnt really do anything, beyond wasting a ton of time.
----
The starting deck might have 60 cards, but right after you draw your initial 7, theres just 53 cards left, and this will further decrease in the game, so you technically need less shuffles to randomize them.
Some might just keep shuffling till some other action is needed in the game (like use a fetchlands and after you pass the turn, you start shuffling, while your opponent is doing his thing, so you can safely shuffle "more", but as soon as something asks you to do something, you stop shuffling and present).
----
All that said, ~7 is quite enough. Some will do less, some more, in the end, the opponent shuffles too, so if both players do their job its working out well enough.
I don't think that people should shuffle 10+ times every time that they shuffle but when you build your deck if you want to randomize it you should shuffle that many times and if you don't want to play against a player that has mana weaved their deck it is a good idea to be thorough when you shuffle their deck. A randomized deck will perform, on average, worse than a mana weaved deck.
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Reprint Opt for Modern!!
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PLAY MORE ROUGE DECKS!
Being a math/computer nerd I wondered if there was a pattern to the reconstructed decks.
Well, it turns out that there is. After some computer simulations and a lot of trial and error number juggling, I derived a formula for predicting the order the cards will be in after a stack shuffle.
Take a deck with n cards listed from the top down as card 0, card 1...card n-1.
I'm starting with zero in my lists because of modulo arithmetic and computer arrays.
Deal them out into s stacks starting with stack 0, stack 1... stack s-1.
Then put stack 1 on top of stack 0, stack 2 on top of stack 1 and continue until stack s-1 is on top.
The card in position x will be in position P(x) afterwards. Where
P(x)=(n-1)-( (x%s) * (n/s) * (x/s) + b )
b= x%s if x%s < n%s
b= n%s if x%s >= n%s
All divisions are integer divisions (truncate the fractional part) and % is modulo division.
I'll explain the terms in the formula.
Since stack shuffling reverses the order of the cards we subtract from (n-1).
If you had only one stack you would simply be reversing the order of the whole deck and the formula would reduce to P(x)=(n-1)-x.
Stack number * Stack size * Position in stack + Shift
(x%s) * (n/s) * (x/s) + b
Shift accounts for using a number of stacks that doesn't divide evenly into the deck size.
That means that the stacks wouldn't all be the same size and the new positions above the larger stacks get shifted up by the difference in size.
Incidentally if you put the stacks back together in reverse order (stack s-1 on the bottom, stack 0 on top)
P(x) = (n-1)- ( (s-1-x%s) * (n/s)*(x/s) +b
b=n%s-x%s-1
if b<0 then b=0
I'm not a competitive Magic player and I don't want this used for cheating.
Quite the opposite, I want this out there so people are aware of it. I'm sure I'm not the only person who thought of it.
It's easily defeated by insisting that the stacks are not put back together in order or doing a riffle shuffle beforehand.
This was just a fun mathematical exercise and I thought some of you other math Magic nerds out there might appreciate it.
On phasing:
Anyway, nice work on the formula!
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You may pile "shuffle" or stack "shuffle" your deck all you want, but it is not random and it is not considered shuffling hence the "". You must mash or riffle shuffle your deck multiple times after each time you pile/stack your deck. About the only good thing pile/stacking your deck does is allows you to count your cards easily because a random deck is absolutely random. People pile then overhand their deck then hand it to me all the time in Japan and then get a judge warning at least 3-4 times a month when I am playing in tournaments because they don't know how to properly shuffle a deck. It's gotten to the point where at the beginning of a round and they hear a judge call they already know what the problem is and start the explanation about why that person is getting a warning and what they should be doing with their deck.
I would absolutely love to break people of the habit of piling their deck because it is a huge waste of time. Pick up your cards after a game and start mashing or riffling what you used in that game to randomize that pile and then mash/riffle the deck and the played cards after that. It will better accomplish what you are trying to do in about half the time. Especially useful if you are a slow player to begin with and go to time often.
Personally I care more about keeping my cards in pristine condition than having them be 100% randomized. I've got a set of Masques Brainstorms I've been playing for more than ten years and they still look like they just came out of a pack. You can hold them up to a light source in an angle and not see any scratches at all. My focus when shuffling is to avoid damaging the cards. Luckily I play in Japan and people here tend to be careful with another dude's cards, but I watch them like a hawk as they start shuffling and if they look like they'll crease the cards I get a judge to shuffle my deck instead. It hasn't come to this yet, but I actually have no problem conceding a match or dropping out of an event to keep my cards mint. Hopefully nobody ever finds out that they can insta-win against me by threatening to bend my cards.
Double sleeve your deck. KMC perfect fits are 200yen in Japan. It's worth it and helps with any bending issues from shuffling. Also helps prevent against moisture getting to the cards. Even a fairly strong mash shuffle shouldn't hurt double sleeved cards.
I totally agree and in fact I already double-sleeve all my decks. I used to have them all in KMC perfect-fits in KMC sleeves, but recently I have been trying out these sturdy-feeling sleeve guards I found at Amenity Dream. They are almost exactly like the ones made by KMC (http://www.hareruyamtg.com/product/80524) except they don't have the silver patterns in the corners and they only cost around Y190. I still use perfect-fits for the cards in my binder.
Note: If you're like me at all, you're thinking right now that the best way to do things is to triple-sleeve the deck in perfect-fits, then a regular sleeve, then a sleeve guard. I've tried this and unfortunately the deck becomes way too thick when you do it that way.
Question: if the person doing the piling did not go sequentially, stack 0, stack 1, ... stack N, though, and kinda haphazardly went from stack 0 to stack N to stack 4, and kept changing it up with each pass, and mashed the piles together, would that impact the ability to accurately predict it at all?
I ask because at least where I am, nobody does their piling sequentially, whereas I have grown fond of piling first, then doing mashes and riffles, and I was curious if sequences, the number of patterns, etc would make it a bit harder to predict mainly because I love to ponder those sorts of things.
Yes, I am a local area mod.WELP. GOOD LIFE CHANGES ALL HAPPEN AT ONCE AND SOME ARE MUTUALLY EXCLUSIVEPrimary Decks:
Modern: Esper Draw-Go
Legacy: RUG Lands
EDH: Sidisi turn-3 storm
Draft my cube! (630 cards)
I absolutely detest whenever anyone tells me that pile shuffling by a number the deck is divisible by isn't as random as shuffling by some arbitrary prime. You do not know what random is! No matter what number you use the deck will not be sufficiently random. No matter what you do your making a neat and ordered deck with minimal clumps! I pile shuffle for three reasons:
1) I'm lazy.
2) No one here is using a sufficiently randomized deck, so why should I put myself at a disadvantage. The alternative is to explain to everyone why they shouldn't shuffle like they are, and once again, I'm lazy.
3) At this REL (And by "this REL" I mean the nonexistant one for casual play) it just doesn't matter and minimizing manascrew is probably just for the best anyway.
Generals meant to be drafted first in a single pack of 6 cards.
And here is the actual cube, meant to be drafted in 4 regular sized packs. (60 card decks)
Its certainly not a good point to "cheat" , and yea, i would count knowingly not shuffling a deck cheating, you are trying to get an advantage.
Its quite easy to combat this, explain it in an open round, not 1 for 1.
That will make up for quite a lot, if they have questions, they can go ahead and any sain person will respect that, especially if its explained by a judge or any half decent person.
If you established this, people should spread the word and if they see someone doesnt shuffle properly, tell them to riffle shuffle, show them how to, its good for everyone.
By that, its totally fine to pile shuffle, count the cards, then riffle quickly and your done. If that becomes routine, its fine, doesnt take even a minute.
Just dont make up the lie that everyone is cheating, so cheating is ok. Thats just the source of all evil, someone has to start and make things go right, its just about anything in life, someone has to make the start and get a respectable front runner to kickstart the process.
If people want to get better, they have to play better, not cheat, its as easy as that.
WUBRG#BlackLotusMatterWUBRG
๐ฎ๐ฎ๐ฎ #BlueLivesMatter ๐ฎ๐ฎ๐ฎ
Keep in mind that this research was for a 52 card deck so a 60 card deck would be less randomized by 7 riffle shuffles than this research indicates.
But still the most reasonable way to shuffle you can archive (without flat out throwing your cards in the air and washing them).
WUBRG#BlackLotusMatterWUBRG
๐ฎ๐ฎ๐ฎ #BlueLivesMatter ๐ฎ๐ฎ๐ฎ
Well, the math behind the number is that that would be the case to archive a random deck in a scenario that isnt really about handling "real" cards.
If you riffle you will archive more and less randomization than the math example would imply, as you might move cards more and in bigger blocks.
What makes riffle shuffles really good randomization is doing them "not" perfect (as putting each 1on1 in exactly half the deck doesnt really do anything).
----
After 7 riffles a deck should be sufficiently random, for any intens and purposes that a game would want to have (especially if the other player performs just like ~2 extra riffles on his own, its as random as it will be and doesnt use too excessive amounts of time).
Doing more and much more shuffling gets to a point in which it simply eats up time and doesnt really archive anything meaningful.
Most will not even do 7 riffles, and just cut and mash like ~3 times.
Usually still enough, especially in Limited, when the opponent then mashes the deck ~2+ times its pretty much sufficient.
----
The most iconic problem with not enough shuffling is when someone can actually predict where a card will end up, which you can easily do, if theres not enough shuffling involved (like the card on the very bottom will be at the bottom after just 3 mash/riffle shuffles, you really need a bunch to fully move cards around).
The classic is when people put like a pile of 10+ lands after a game in there deck, and riffle/mash that just like 3 times. Ofcourse that stack of lands wont really disappear from that, and so they end up hurting themselves (and dont know they did it on their own).
Commonly people will "learn" to mana-weave their deck, which will avoid that problem, but only really means they shuffle even less, and "think" they do the right thing, as it clearly doesnt hurt them anymore.
At some point if people understand what they are doing, they will shuffle more, but here again comes a point where people shuffle so much that it doesnt really do anything, beyond wasting a ton of time.
----
The starting deck might have 60 cards, but right after you draw your initial 7, theres just 53 cards left, and this will further decrease in the game, so you technically need less shuffles to randomize them.
Some might just keep shuffling till some other action is needed in the game (like use a fetchlands and after you pass the turn, you start shuffling, while your opponent is doing his thing, so you can safely shuffle "more", but as soon as something asks you to do something, you stop shuffling and present).
----
All that said, ~7 is quite enough. Some will do less, some more, in the end, the opponent shuffles too, so if both players do their job its working out well enough.
WUBRG#BlackLotusMatterWUBRG
๐ฎ๐ฎ๐ฎ #BlueLivesMatter ๐ฎ๐ฎ๐ฎ